Refurbished beverage storage tank

ABSTRACT

A method of refurbishing a beverage storage tank having a lined interior surface. The interior surface of the beverage storage tank is sprayed with a fluid jet to remove lining and surface contaminates from the beverage storage tank. The interior surface of the beverage storage tank is abrasive blasted to prepare the interior surface of the beverage storage tank, and a beverage safe coating material is applied to the prepared interior surface of the beverage storage tank.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to beverage storage tanks, and more particularly, to a method of refurbishing a beverage storage tank and the resulting tank.

[0002] Beverage storage tanks are used at beverage production facilities to store and/or age beverages such as beer. Conventional beverage storage tanks comprise a carbon steel shell having a glass lining to prevent the beverage from contacting the shell. The lining protects the tank from being chemically degraded by the beverages. Further, because the glass lining is inert, it does not react with the beverages in the tank. However, over time the lining can become chipped and/or cracked allowing beverage to contact the shell and rendering the lining ineffective. Thus, there is a need for a method of replacing the glass lining to refurbish used beverage storage tanks.

[0003] Because the storage tanks are large, they cannot be easily removed from the beverage production facility to an off site location for refurbishment. Further, applying a new glass lining to the tank while it is in the beverage production facility is problematic due to potential contamination of adjacent tanks and/or production down time. Thus, there is a need for a method of refurbishing storage tanks on site at the beverage production facility using an inert lining material other than glass.

SUMMARY OF THE INVENTION

[0004] Briefly, the present invention includes a method of refurbishing a beverage storage tank having a lined interior surface. The interior surface of the beverage storage tank is sprayed with a fluid jet to remove lining and surface contaminates from the beverage storage tank. The interior surface of the beverage storage tank is abrasive blasted to prepare the interior surface of the beverage storage tank, and a beverage safe coating material is applied to the prepared interior surface of the beverage storage tank.

[0005] In another aspect, the invention includes a refurbished beverage tank comprising a metal shell having an interior surface defining an interior volume of the beverage tank sized and shaped for holding a predetermined amount of beverage. In addition, the beverage tank includes a beverage safe coating material applied to the interior surface of the metal shell. The metal shell and the beverage safe coating material are joined at the interior surface having a cleanliness, when viewed without magnification, free of all visible oil, grease, dust, dirt, mill scale, rust, coating, oxides, corrosion products and other foreign matter.

[0006] Other features of the present invention will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a perspective of a prior art tank in partial section; and

[0008]FIG. 2 is a perspective of a tank of the present invention in partial section.

[0009] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0010] Referring now to the drawings and in particular to FIG. 1, a conventional beverage storage tank is designated in its entirety by reference numeral 20. The storage tank 20 includes a metal shell 22 having an interior surface 24 defining an interior volume 26 sized and shaped for holding a predetermined amount (e.g., 500 bbL to 1500 bbL) of beverage such as beer. Although the shell 22 may be made of other materials without departing from the scope of the present invention, in one embodiment the shell is made of a carbon steel. Although the shell 22 may have other shapes without departing from the scope of the present invention, in one embodiment the shell has a conventional cylindrical shape with dome-shaped ends 28. A covered manhole 30 provides access to the interior volume 26 for servicing and cleaning the tank 20. The tank 20 also includes an inlet 32 for delivering beverage to the tank and an outlet 34 for removing beverage from the tank. The interior surface 24 of the tank 20 is lined with a conventional non-reactive protective lining 36 such as glass or a thin film of epoxy. As the features of the tank 20 are conventional, other aspects of the tank will not be described in detail. Over time, the lining degrades, permitting beverage to contact and react with the shell 22.

[0011] As illustrated in FIG. 2, a refurbished beverage storage tank of the present invention is designated in its entirety by the reference numeral 40. The refurbished storage tank 40 has all of the same features as the conventional tank 20 (FIG. 1) except that the interior surface 24 of the refurbished tank 40 is coated with an improved beverage safe coating material 42 instead of the conventional lining 36 (FIG. 1). Although other coating materials may be used without departing from the scope of the present invention, in one embodiment the coating material 42 is an epoxy polymer such as a polymer sold under the trade name IECC 30-50 Amber Glass by Industrial Environmental Coatings Corporation of Pompano Beach, Fla. The metal shell 22 and the beverage safe coating material 42 are joined at an interface 44 between the shell and coating material having a cleanliness when viewed without magnification sufficient to be visually free of foreign matter such as oil, grease, dust, dirt, mill scale, rust, coating, oxides, and/or corrosion products. Preferably, the coating material 42 is applied to the interior surface 24 of the metal shell 22 so the material is free of cold joints thereby making the material less likely to crack prematurely. Although the material 42 may have other thicknesses without departing from the scope of the present invention, in one embodiment the coating material has a thickness 44 between about 0.03 inch and about 0.05 inch. Thicknesses less than about 0.03 inch offer less than desirable protection for the interior surface 24 of the metal shell 22. Thicknesses greater than about 0.05 inch can result in poor adhesion and appearance.

[0012] To produce the refurbished tank 40 as described above, the conventional tank 20 is removed from service and beverage is drained from the tank using conventional procedures. Once the tank 20 is empty, workers enter the manhole 30 and begin processing. In one embodiment of the present invention, the lining 36 and any surface contaminates are removed by blasting the interior surface 24 of the tank with an abrasive material. Although other media may be used for the abrasive blast without departing from the scope of the present invention, in one embodiment the media comprises a steel grit having a blast profile between about 0.03 inch and about 0.05 inch. Further, in one embodiment the material is recyclable and is used exclusively for removing lining from tanks that hold beverages and/or other foods to prevent contamination of the tank and surrounding area. In addition, it is desirable to inspect the abrasive material frequently during use to ensure it is free of traces of oil and other foreign contaminants. In the event contaminants are found, the abrasive material may be discarded or reconditioned using conventional methods. A conventional abrasive recovery system may be used to remove abrasive from the tank. A dust collection system may be used during abrasive blasting to reduce airborne particulate. Other standard practices, and particularly conventional dust reduction practices, may be observed. Although other blasting parameters may be used without departing from the scope of the present invention, in one embodiment the blasting operation is performed at a minimum of 100 pounds per square inch. About 1300 cubic feet per minute of dry air may be required to meet this requirement. In an alternate embodiment, the abrasive blasting step may be performed using a conventional abrasive slurry system rather than a dry system.

[0013] After abrasive blasting, a final cleaning step may be performed to eliminate residual blast material and contaminates. For example, magnetic brooms, vacuums and other conventional means may be used to remove the material and contaminates. Further, it may be advisable for personnel performing the abrasive blasting procedure to change their outer clothing prior to the final cleaning step.

[0014] Once the interior surface 24 is prepared using the lining removal process described above, the interior surface of the tank is visually inspected in ensure the interior surface meets The Society for Protective Coatings (Pittsburgh, Pa.) Standard SSPC-SP-5 for white metal grade. Generally, this standard requires that interior surface 24 have a cleanliness when viewed without magnification sufficient to be visually free of foreign matter such as oil, grease, dust, dirt, mill scale, rust, coating, oxides, and/or corrosion products.

[0015] In another embodiment that is particularly useful for refurbishing conventional tanks 20 having thin film linings rather than glass linings, the lining 36 is removed using an ultra-high pressure water jet. Although other fluid jets may be used without departing from the scope of the present invention, in one embodiment the fluid jet is a water soluble contaminate remover such as Chlor*Rid available from from Chlor Rid International Incorporated of Chandler, Ariz. Further, although the fluid jet may be discharged at other pressures, in one embodiment the fluid jet is sprayed at a pressure of about 40,000 pounds per square inch. Once the lining 36 is removed, the interior surface 24 is abrasive blasted as described above so the surface meets the SSPC-SP-5 white metal grade standard described above.

[0016] After the lining 36 has been removed and the interior surface 24 is inspected to ensure it meets the white metal grade standard, the interior is power washed and given a final rinse with Chlor*Rid cleaning preparation to remove residual salts and other contaminants. Although the power wash may be performed using other parameters without departing from the scope of the present invention, in one embodiment the power wash is performed with hot water (e.g., about 90 degrees Fahrenheit) sprayed at a pressure of about 2500 pounds per square inch. The Chlor*Rid preparation is applied at a strength of between about 300 square feet per gallon and about 500 square feet per gallon.

[0017] After inspection and decontamination, the beverage safe coating material 42 is applied to the interior surface 24 of the shell 22. Although other coating materials may be used without departing from the scope of the present invention, in one embodiment the coating material is an epoxy polymer such as the previously mentioned IECC 30-50 Amber Glass material. Further, although the material may be applied to other thicknesses without departing from the scope of the present invention, in one embodiment the coating material is applied to a thickness greater than about 0.03 inch. In another embodiment, the material is applied to a thickness between about 0.03 inch and about 0.05 inch. Moreover, in one embodiment the coating material is applied using a 4/0.029 nozzle at a pressure of about 2700 pounds per square inch and a temperature between about 90 degrees Fahrenheit and about 130 degrees Fahrenheit. The coating material may be heated using a conventional heater and mixed using a conventional mixing unit prior to being applied. Still further, in one embodiment the interior of the tank is maintained at a humidity below about 50 percent during abrasive blasting and coating material application. A conventional dehumidifier may be used to maintain the desired maximum humidity. The coating material is cured after application to the interior surface of the beverage storage tank. During curing, the interior of the beverage storage tank is maintained at a temperature of about 70 degrees Fahrenheit for 24 hours. A conventional insulation blanket and/or a thermal blanket may be used to maintain this temperature. After this minimum curing time, the coating material is Shore hardness tested. A minimum Shore D hardness of 75 is required. If the minimum hardness is not met, additional curing is required. After curing, the coating material 42 is visually inspected for defects such as runs, sags and voids. Further, in one embodiment the coating material is inspected using conventional Holiday detection equipment to ensure total coating material coverage and that the minimum thickness of the coating material is achieved.

[0018] Prior to applying the coating, large divots (e.g., having a diameter greater than about {fraction (1/8)} inch) in the interior surface 24 of the shell 22 may be patched using an IECC Amber Glass patch kit available from Industrial Environmental Coatings Corporation.

[0019] When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0020] As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 

What is claimed is:
 1. A method of refurbishing a beverage storage tank having a lining and an interior surface, comprising the steps of: spraying the interior surface of the beverage storage tank with a fluid jet to remove the lining and surface contaminates from the beverage storage tank; abrasive blasting the interior surface of the beverage storage tank to prepare the interior surface of the beverage storage tank; and applying a beverage safe coating material to the prepared interior surface of the beverage storage tank.
 2. A method as set forth in claim 1 wherein the fluid jet comprises a water soluble contaminate remover.
 3. A method as set forth in claim 1 wherein the fluid jet is sprayed at a pressure of about 40,000 pounds per square inch.
 4. A method as set forth in claim 1 wherein the abrasive blast media comprises steel grit.
 5. A method as set forth in claim 4 wherein the steel grit has a blast profile between about 0.03 inch and about 0.05 inch.
 6. A method as set forth in claim 1 wherein the beverage safe coating material comprises an epoxy polymer.
 7. A method as set forth in claim 1 wherein the beverage safe coating material is applied to a thickness greater than about 0.03 inch.
 8. A method as set forth in claim 7 wherein the beverage safe coating material is applied to a thickness between about 0.03 inch and about 0.05 inch.
 9. A method as set forth in claim 1 wherein the beverage safe coating material is applied at a pressure of about 2,700 pounds per square inch.
 10. A method as set forth in claim 1 wherein the beverage safe coating material is heated to a temperature greater than about 90 degrees Fahrenheit prior to application.
 11. A method as set forth in claim 1 further comprising spraying the interior surface of the beverage storage tank with water to remove the lining prior to abrasive blasting.
 12. A method as set forth in claim 11 wherein the water is sprayed at a pressure of about 40,000 pounds per square inch.
 13. A method as set forth in claim 1 wherein an interior of the tank is maintained at a humidity below about 50 percent during abrasive blasting and coating material application.
 14. A method as set forth in claim 1 wherein the beverage safe coating material is cured after application to the interior surface of the beverage storage tank.
 15. A method as set forth in claim 14 wherein an interior volume of the beverage storage tank is maintained at a temperature of about 70 degrees Fahrenheit during curing.
 16. A refurbished beverage storage tank comprising: a metal shell having an interior surface defining an interior volume of the beverage storage tank sized and shaped for holding a predetermined amount of beverage; and a beverage safe coating material applied to the interior surface of the shell, wherein the metal shell and the beverage safe coating material are joined at the interior surface having a cleanliness when viewed without magnification sufficient to be visually free of foreign matter.
 17. The refurbished beverage storage tank as set forth in claim 16 wherein the foreign matter comprises at least one of a oil, grease, dust, dirt, mill scale, rust, coating, oxides, and corrosion product.
 18. The refurbished beverage storage tank as set forth in claim 16 wherein the beverage safe coating material is applied free of cold joints.
 19. The refurbished beverage storage tank as set forth in claim 16 Wherein the beverage safe coating material is an epoxy polymer.
 20. The refurbished beverage storage tank as set forth in claim 16 wherein the beverage safe coating material has a thickness greater than about 0.03 inches. 